Two case reports with Myxoid and Pleomorphic varieties of Malign Fibrohistiocytoma are presented. In both cases, the first consult took place in an Angiology and Vascular Surgery Service, because their clinical symptoms were similar in the first case to such produced by the arteriovenous fistulas and in the second case, symptoms remaid to an hematoma secondary to a varicose vein rupture. Such rare and malign tumors often are diagnosed as vascular diseases, and they may be discovered in the usual clinical practice, so its important an accurate recognition as well as an adequate treatment.